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Observatory

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An observatory is a specialized location used to observe various events. These sites allow scientists to study the Earth and the universe. Different fields use them for specific purposes. Astronomers use them to study celestial objects like stars. Climatologists and meteorologists use them to study weather and climate. Geophysicists, oceanographers, and volcanologists also use observatories to study the physical world.

Royal observatory Greenwich
Royal observatory Greenwich

Astronomical observatories are categorized by where they are located. There are four main types: space-based, airborne, ground-based, and underground-based. Ground-based observatories sit on the Earth's surface. They often use optical telescopes to see visible light. Most optical telescopes are kept inside a protective dome. This dome has a slit in the roof that opens to the sky. The entire upper portion of the dome can rotate. This allows the telescope to point at different sections of the night sky.

Radio observatories are a different type of ground-based facility. They use instruments to observe the radio portion of the electromagnetic spectrum. These facilities include control centers, data reduction centers, and maintenance buildings. Unlike optical telescopes, radio telescopes usually do not need domes. They are often placed in valleys to provide shielding from electromagnetic interference (EMI). This interference comes from devices like TV, radar, and radio signals. Major radio observatories include the Very Large Array in New Mexico and Jodrell Bank in the UK.

Finding the perfect location for a ground-based observatory is a precise science. Modern optical observatories need dark skies and many clear nights. They also require dry air and high elevations. At high elevations, the atmosphere is thinner. This reduces atmospheric turbulence, which improves what scientists call "seeing." The best locations include Hawaii, the Canary Islands, and the Andes. A 2009 study found that Ridge A in Eastern Antarctica is the best possible location on Earth. This site provides the least atmospheric disturbance and the best visibility.

Some observatories are built at extremely high altitudes to reach thinner air. Since the mid-20th century, many have been placed high above the clouds. The Mauna Kea Observatory in Hawaiʻi is one of the most notable. The Chacaltaya Astrophysical Observatory in Bolivia was the highest permanent observatory for many years. It was built in the 1940s but was surpassed in 2009. Now, the University of Tokyo Atacama Observatory in Chile is a leading high-altitude site.

Observatorio-cba
Observatorio-cba

Space-based observatories orbit the Earth to avoid the atmosphere entirely. The Earth's atmosphere is opaque to certain types of light. It blocks ultraviolet radiation, X-rays, and gamma rays. It also partially blocks infrared radiation. Space telescopes can see these wavelengths clearly. They also provide much higher angular resolution because they are not affected by atmospheric turbulence.

Hubble Space Telescope (27946391011)
Hubble Space Telescope (27946391011)

However, space telescopes are very expensive to build. They are also extremely difficult to maintain. While the Hubble Space Telescope was serviced by Space Shuttles, many others cannot be repaired.

Airborne observatories offer a middle ground between ground and space. These use airplanes to reach higher altitudes. This puts them above much of the Earth's atmosphere. This is helpful for observing infrared light, which water vapor absorbs. The Stratospheric Observatory for Infrared Astronomy (SOFIA) is a notable example.

SOFIA with open telescope doors
SOFIA with open telescope doors

Airborne observatories are easier and cheaper to repair than space telescopes. They can be updated and deployed much more quickly.

Observatories have a long and diverse history. Ancient people used "proto-observatories" to track astronomical phenomena. Examples include Stonehenge in Great Britain and Chankillo in Peru. The first true research institutes appeared much later. The Al-Shammisiyyah Observatory in Baghdad was established in 825. The Royal Greenwich Observatory in England was established in 1675.

Royal observatory Greenwich
Royal observatory Greenwich

Throughout the 1700s and 1800s, many more institutions were founded globally. These sites helped transition astronomy into a modern scientific discipline.

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🖼️ Images & Media (4)
File:Royal observatory Greenwich.JPG
Royal observatory Greenwich.JPG
File:Hubble Space Telescope (27946391011).jpg
Hubble Space Telescope (27946391011).jpg
File:SOFIA with open telescope doors.jpg
SOFIA with open telescope doors.jpg
File:Observatorio-cba.jpg
Observatorio-cba.jpg
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